JQuery Mobile Pinch Zoom Image Only

you can do this on image:

var image=document.getElementById('imageId');

image.addEventListener('gesturechange',function(e){

    if(e.scale>1){
        //zoom in 
        //increase the size of image according to the e.scale
    }

    else if(e.scale<1){
        //zoom out 
        //decrease the size of image according to the e.scale
    }
});